Written by Erin Oliver
You are nearing your destination on an IFR flight, and have just left the airway on an ATC vector to the final approach course. You now want to activate the approach procedure that you had previously loaded in to your Garmin GPS flight plan. You're on a vector, right? Shouldn't you just push the PROC key and select "Activate Vectors-To-Final?"
I am not a fan of the "Vectors-To-Final" method of activating the instrument approach in the Garmin GPS. Here's why:
Let's use the ILS runway 24 approach at Palomar, California (KCRQ) (see below), as an example. You are coming from Oceanside VOR, and ATC says "Fly heading 060, radar vectors to final". You synch up the HDG bug, push HDG on the autopilot, twist the bug to 060 degrees, and then you push the PROC key and activate "Vectors-To-Final" in the GPS.
At this point, the only approach waypoints that your GPS Flight Plan (FPL) will load are your Final Approach Fix (FA) at DEASY, and the Missed Approach Point (MA). You see NONE of the other waypoints that appear on your paper approach chart! (Compare this with what you will see in the Flight Plan when you load the instrument approach using any Initial Approach fix (IA), such as the nearby HOMLY instersection. Now, you will get to see ALL the approach waypoints that are on the paper chart for that transition).
So here's the potential trap: With "Vectors-To-Final" activated, and only your FA and MA showing on the Garmin, ATC now tells you, "Turn right, heading 210, cross ESCON at or above 3500 cleared for the ILS". ESCON is not the FA, and so doesn't appear in your flight plan! You now have to scramble to figure out what your position is, relative to ESCON, so you don't bust your crossing restriction. Or maybe ATC asks you to say your distance from ESCON. Same thing - it is not in your flight plan, because when you selected "Activate Vectors-To-Final", only the FA and the MA were loaded as appraoch waypoints.
To avoid this trap, here's the way I like to set up my Garmin GPS when ATC begins vectoring me to the final approach course:
I always initially LOAD (not activate) my approaches with a transition from an Initial Approach fix (IA)-- preferrably the one nearest my actual position (Homly intersection, in this example). It doesn't matter that we won't actually fly to the IA, we just want the FPL to show us all the same waypoints that we see on our paper chart, or for those of us with WAAS, on the e-chart. When ATC begins to vector us for the approach, I put the autopilot in HDG mode, and turn to the assigned heading. Then I push the FPL key, get my cursor and highlight the FA (in this example, DEASY), push MENU and choose "ACTIVATE LEG?". This will keep the GPS up with the approach while PRESERVING ALL THE FIXES ON THE APPROACH. Much, much better for situational awareness, and the autopilot can still inercept final and track it in GPSS mode, no matter how far out on final you happen to capture the course. (Remember to switch the Garmin to VLOC mode and the autopilot to APR while tracking inbound on the ILS localizer.)
In summary: For best situational awareness, load your instrument approaches into the Garmin using an Initial Approach Fix (IA), and when you get your first radar vector for final, highlight the FA, and choose "Activate Leg", not "Activate Vectors-to-Final"
Regional Manager, Los Angeles CA
19 Dec 2008 10:01